Re: [PATCH] fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers

["Ted Ts'o" <tytso@mit.edu>]

On Wed, Jun 29, 2011 at 02:05:16PM -0400, Josef Bacik wrote:
> diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
> index ce66d2f..da3bed3 100644
> --- a/fs/ext4/fsync.c
> +++ b/fs/ext4/fsync.c
> @@ -151,6 +151,32 @@ static int ext4_sync_parent(struct inode *inode)
>  	return ret;
>  }
>  
> +/**
> + * __sync_file - generic_file_fsync without the locking and filemap_write
> + * @inode:	inode to sync
> + * @datasync:	only sync essential metadata if true
> + *
> + * This is just generic_file_fsync without the locking.  This is needed for
> + * nojournal mode to make sure this inodes data/metadata makes it to disk
> + * properly.  The i_mutex should be held already.
> + */
> +static int __sync_inode(struct inode *inode, int datasync)

The comment calls this __sync_file, instead of __sync_inode.

Maybe it would be better to define a generic_file_fsync_nolock() in
fs/libfs.c and then have generic_file_fsync() call the _nolock()
function?  That way we don't have the code duplicated in two different
places, and eventually risking it going out of sync with each other.

	    	       	       	  	- Ted